1. Field of the Invention
The present invention pertains to systems and methods for measuring multiphase fluid flow, particularly combined flows of crude oil, water and gas produced from a hydrocarbon bearing formation. The systems use calorimetric liquid phase measurement techniques combined with density measurement and measurements based on the dielectric properties of a multicomponent liquid.
2. Background
There are several process and transport applications wherein the flow rates of the components of a multiphase fluid must be determined. One particularly vexatious application is in regard to the production of well fluids from a subterranean hydrocarbon bearing formation. The accurate determination of the amounts of the respective component in a mixture, primarily comprising oil, water and gas, is important from an economic and regulatory standpoint, in particular. Moreover, the requirements for measuring the flow from a well or a combined flowstream from several wells using prior art methods may be aggravated by space requirements in certain locations, such as offshore production platforms and liquid gathering and processing systems operating in adverse climates such as Arctic regions.
It is also important that a sample be measured which is representative of the full flowstream of fluid being produced and transported so as to avoid errors associated with conventional methods for measuring so-called slipstream samples. It is also desirable that the flow measuring apparatus be reliable and not subject to measurement errors when operating at conditions wherein the fluids being monitored may be a high percentage of one phase at a particular time and then go through a substantial change in the makeup of the fluid stream. Certain oil producing formations are subject to such wide variations in the flow of water, oil and gas, respectively, as the formation is produced.
With these problems and desiderata apparent in the art of multiphase flow measurement, there has been a continuing effort to develop systems and methods for measuring multiphase fluid flow. The present invention provides systems and methods which are believed to be advantageous and solve many of the problems mentioned herein, as well as overcoming deficiencies of prior art systems and methods.